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Ch.21 - Nuclear Chemistry
Chapter 21, Problem 16

What particle is produced during the following decay processes: (a) sodium-24 decays to magnesium-24, (b) mercury-188 decays to gold-188, (d) plutonium-242 decays to uranium-238?

Verified step by step guidance
1
Identify the type of decay process for each reaction. For (a) sodium-24 to magnesium-24, check if the atomic number decreases by 1, indicating beta-plus decay (positron emission).
For (a), write the nuclear equation: \( \text{^{24}_{11}Na} \rightarrow \text{^{24}_{12}Mg} + \text{^{0}_{+1}e} \). The particle produced is a positron \( \text{^{0}_{+1}e} \).
For (b) mercury-188 to gold-188, check if the atomic number decreases by 1, indicating beta-plus decay (positron emission).
For (b), write the nuclear equation: \( \text{^{188}_{80}Hg} \rightarrow \text{^{188}_{79}Au} + \text{^{0}_{+1}e} \). The particle produced is a positron \( \text{^{0}_{+1}e} \).
For (d) plutonium-242 to uranium-238, check if the mass number decreases by 4 and the atomic number decreases by 2, indicating alpha decay. Write the nuclear equation: \( \text{^{242}_{94}Pu} \rightarrow \text{^{238}_{92}U} + \text{^{4}_{2}He} \). The particle produced is an alpha particle \( \text{^{4}_{2}He} \).

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Nuclear Decay

Nuclear decay is a process by which an unstable atomic nucleus loses energy by emitting radiation. This can occur in various forms, including alpha decay, beta decay, and gamma decay. Understanding the type of decay is crucial for predicting the particles produced and the resulting elements.
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Alpha and Beta Particles

Alpha particles consist of two protons and two neutrons, essentially a helium nucleus, and are emitted during alpha decay. Beta particles are high-energy, high-speed electrons or positrons emitted during beta decay. Identifying whether a decay process involves alpha or beta emission helps determine the resulting element and its atomic structure.
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Characteristics of Beta Particles

Mass Number and Atomic Number

The mass number is the total number of protons and neutrons in an atomic nucleus, while the atomic number is the number of protons. During decay processes, these numbers change, leading to the formation of new elements. Understanding how these numbers shift during decay is essential for predicting the products of nuclear reactions.
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